Crosswinds keep shuttle on ground

"Naturally, we're disappointed that weather kept us from getting into orbit today . . . We're anxious to get to work on our Hubble servicing tasks," mission commander Dick Covey said after he and the six other crew members left the shuttle Endeavour.

NASA rescheduled the flight for tomorrow at 4:27 a.m. Weather forecasters, however, predict cloudy skies may ground the shuttle again.

The decision to scrub today's mission came within seven minutes of the 6:04 a.m. close of the shuttle's launch window. As the minutes ticked away, launch director Robert B. Seich monitored a series of conditions that threatened to keep Endeavour from blasting off toward its much anticipated rendezvous with the blurry-eyed space telescope. During the 11-day mission, NASA's most ambitious and complex since the Apollo moon landing, the Endeavour crew will attempt five space walks to repair Hubble's flawed vision and replace worn parts that threaten the planned 15-year life span of the observatory.

Although the moon shone brightly in the blue-black night, persistent crosswinds, light rainshowers and a low cloud ceiling within the launch arena posed the greatest problems for liftoff. Then NASA was alerted to "an intruder offshore" -- a tanker motoring in an area of the ocean where the shuttle's rocket boosters would drop off after launch. The vessel eventually reponded to Coast Guard's calls to move out of the area.

In the end, with less than seven minutes remaining for a possible liftoff, the wind kept the birdlike shuttle in its perch. "It looks like the winds are beyond our control," launch director Robert Sieck told the astronaut crew shortly before 6 a.m. "We'll call it a scrub. Maybe we'll have better luck tomorrow."

What concerned NASA was the speed of the winds at the shuttle landing facility, an area several miles from the launch pad where Endeavour would have to land should it experience problems after liftoff. Weather forecasters clocked the winds at 16-18 knots, beyond the allowable 15-knot limit.

David Leckrone, a Hubble project scientist at the Goddard Space Flight Center in Greenbelt, Md., was among the disappointed waiting in the chill darkness for Endeavour to blast off.

"It seemed like a nice enough morning by many standards," said Dr. Leckrone. "On the other hand, we've got to do it right."

While the winds may be less swift tomorrow, weather forecasters here say low-hanging clouds may keep the shuttle again in its berth. Air Force Capt. Dean Hazen said overall weather conditions predicted for tomorrow were improved over today's. The mission has a 60 percent chance of flying tomorrow, he said.

"[Cloud] ceiling will be the primary concern tomorrow," Captain Hazen said early today.

The shuttle mission has been in the works for three years, ever since NASA discovered the flaw in Hubble's primary mirror two months after its April 1990 launch. The telescope is NASA's window into the universe. By correcting Hubble's optical problems, NASA hopes to restore the full potential of the telescope's scientific capabilities.

The telescope was designed to enable astronomers to search for planets orbiting other stars, verify the existence of black holes at the center of distant galaxies, study the evolution of galaxies and measure the age of the universe.

The success of the mission, as defined by NASA, depends on the number of tasks the crew accomplishes while in space. At a minimum, NASA hopes to correct Hubble's focusing problem for at least one of its astronomical instruments, and replace at least one broken gyroscope.

On the third day of the mission, the shuttle is scheduled to rendezvous with the Hubble telescope, which is orbiting about 377 miles above Earth. The crew will use Endeavour's mechanical arm to pull the 48-foot-long telescope into the shuttle bay, where it will be secured and repaired. Then their work will begin.

If the mission is successful, NASA hopes to extend Hubble's vision to the farthest reaches of the universe, and to see objects 10 to 15 times fainter than those visible now.